1. Field of the Invention
The present invention relates to a hermetic reciprocating compressor, more particularly, a baffle plate of a discharge muffler for a hermetic reciprocating compressor, which reduces flow noise generated by high pressure refrigerant which is discharged through a discharge chamber of a cylinder head into the discharge muffler.
2. Description of the Related Art
Generally, a hermetic reciprocating compressor is operated to compress a refrigerant at a high pressure and a high temperature through a refrigerating cycle and discharge the refrigerant out of a housing of the hermetic reciprocating compressor. In the refrigerating cycle, the refrigerant is sequentially compressed, condensed, expanded and evaporated.
As shown in FIGS. 4-6, a conventional hermetic reciprocating compressor comprises a sealed housing 10 which is divided into an upper housing 11 and a lower housing 12, a driving part 20 which is disposed in the sealed housing 10 and a compressing part 30 which receives a driving force from the driving part 20 so as to suck and compress a refrigerant.
The driving part 20 is disposed at an upper portion of the sealed housing 10 and is provided with a stator 21 which is fixed to a cylinder block 32 in the lower housing 12, a rotor (not shown) which generates a magnetic field and a rotational shaft 22 which is rotatably coupled to the rotor and is integrally formed with an eccentric shaft 23 at a lower portion thereof.
In addition, the compressing part 30 is mounted at the lower housing 12 and comprises a cylinder head 31 which is formed with a suction chamber (not shown) and a discharge chamber (not shown) for guiding the refrigerant which is sucked and discharged, the cylinder block 32 which a compressing chamber (not shown) is provided therein, a piston (not shown) which is reciprocated in the compressing chamber and a connecting rod 33 which connects the piston with the eccentric shaft 23 and converts a rotational motion into a rectilinear motion.
On an upper portion of the cylinder head 31, there is provided a suction muffler 40 in which an inlet port 41 is formed. The inlet port 41 guides the refrigerant to the cylinder head 31 and excludes a noise which is generated upon refrigerant introduction. The suction muffler 40 is connected with a refrigerant guiding pipe 50 which guides the refrigerant introduction from an external portion of the sealed housing 10.
Meanwhile, on both ends of the cylinder block 32, there are respectively provided discharge mufflers 80 each of which is communicated through a communicating aperture 60 with the discharge chamber of the cylinder head 31. The discharge muffler 80 is served as a noise excluding device which reduces a flow noise due to the discharging of the high pressure refrigerant.
In such hermetic reciprocating compressor, when power source is applied, the compressing part 30 and the driving part 20 are operated.
That is, the stator 21 and the rotor are reciprocally acted so that the rotational shaft 22 is rotated along with the rotor. The piston, which is connected through the connecting rod 33 with the eccentric shaft 22 of the rotational shaft, is reciprocated in the compressing chamber. The refrigerant is sucked through the suction muffler 40 and the suction chamber of the cylinder head 31, and compressed at a high pressure, and then discharged through the discharge chamber of the cylinder head 31 and the communicating aperture 60 to the discharge muffler 80.
In the discharging process of the refrigerant, when the piston is moved to a bottom dead point, the refrigerant is sucked at a low pressure. And when the piston is moved to an upper dead point, the refrigerant is compressed at a high temperature and sequentially discharged to the discharge chamber of the cylinder head 31.
Then, the refrigerant is discharged through the communicating aperture 60 to the discharge muffler 80. Eventually, the compressed refrigerant is discharged from the muffler 80 through a discharge pipe 86 communicated with an inner portion of the discharge muffler 80 to the outside of the sealed housing 10.
The discharge muffler 80 temporarily stores the high pressure refrigerant so as to reduce the discharge noise, as shown in FIGS. 4 to 6. That is, on each end of the cylinder block 32, there is provided an installing part 70 on which the discharge muffler 80 is mounted. An aperture 71 having a thread therein is formed at a center portion of the installing part 70.
And, the discharge muffler 80 is coupled to the installing part 70. The discharge muffler 80 includes a hemispherical cover 81 which is coupled to the installing part 70 so as to form an inner space and a hemispherical baffle plate 82 which divides the inner space into an upper part and a lower space. The baffle plate 82 is recessed downward.
In addition, on each upper and lower part of an outer circumference, there is provided a gasket 83 for preventing a leakage of the refrigerant. The baffle plate 82 and the cover 81 are respectively formed with a bolt hole 84, 85 at center portion thereof.
Therefore, the upper space of the discharge muffler 80 is communicated through the communicating aperture 60 with the discharge chamber of the cylinder head 31 so that the high pressure refrigerant is introduced. The refrigerant is then introduced through the bolt hole 84 of the baffle plate 82 into the lower space of the discharge muffler 80 so as to be temporarily stored therein.
And, the discharge pipe 86 for guiding the high pressure refrigerant to the outside of the sealed housing 10 is connected with the cover 81.
The installing order of the discharge muffler 80 will be described more fully. First, the hemispherical baffle plate 82 having the upper and lower gaskets 83 is fitted with the hemispherical cover 81 of the discharge muffler 80. The cover 81 and baffle plate 82 are fixed to the cylinder block 32 by a bolt 90 provided with a washer 91 which is screwed through the bolt holes 84, 85.
Therefore, the discharge muffler 80 is formed with the inner space between the installing part 70 of the cylinder block 32 and the cover 81. Further, the inner space is divided into the upper space and the lower space by the baffle plate 82. Thus, when the high pressure refrigerant is discharged through the communication aperture 60 from the discharge chamber, the flow noise due to a different of flow speed of the refrigerant is reduced in the muffler. Then, the refrigerant is discharged through the discharge pipe 86 connected with a lower portion of the cover 81 to the outside.
However, since the inner space of the discharge muffler 80 is simply partitioned into the upper and lower spaces, there is a limit to the reducing of the noise which is generated when the high pressure and the high temperature refrigerant is discharged. Therefore, there is a problem that the vibration and noise by the high pressure refrigerant is directly transmitted to a refrigerating cycle.
It is therefore an object of the present invention to provide a baffle plate of a discharge muffler for a hermetic reciprocating compressor, which is provided with a duct extended to the cover at a center of a baffle plate thereof so as to increase a reducing efficiency of flow noise.
To achieve the above objects and other advantages, there is provided a baffle plate of a discharge muffler for a hermetic reciprocating compressor which is mounted in an inner portion of the discharge muffler mounted at a lower portion of a cylinder block so as to reduce flow noise of a refrigerant discharged to a discharge pipe, characterized in that an extended duct, which is communicated from a center portion of the baffle plate to the discharge pipe and has a diameter, is formed during a press molding.